diff --git a/gc.c b/gc.c
index fa903752bf111e..d0dc70ff7fb356 100644
--- a/gc.c
+++ b/gc.c
@@ -2709,29 +2709,34 @@ count_objects_i(VALUE obj, void *d)
 
 /*
  *  call-seq:
- *     ObjectSpace.count_objects([result_hash]) -> hash
+ *     ObjectSpace.count_objects(result_hash = {}) -> hash
  *
- *  Counts all objects grouped by type.
+ *  Counts the number of objects, grouped by type.
  *
- *  It returns a hash, such as:
- *	{
- *	  TOTAL: 10000,
- *	  FREE: 3011,
- *	  T_OBJECT: 6,
- *	  T_CLASS: 404,
- *	  # ...
- *	}
+ *  It returns a hash that looks like:
  *
- *  The contents of the returned hash are implementation specific.
- *  It may be changed in future.
+ *    {
+ *      TOTAL: 10000,
+ *      FREE: 3011,
+ *      T_OBJECT: 6,
+ *      T_CLASS: 404,
+ *      # ...
+ *    }
  *
- *  The keys starting with +:T_+ means live objects.
+ *  The contents of the returned hash are implementation specific and
+ *  may be changed in future versions without notice.
+ *
+ *  The keys starting with +:T_+ are live objects of a particular type.
  *  For example, +:T_ARRAY+ is the number of arrays.
- *  +:FREE+ means object slots which is not used now.
- *  +:TOTAL+ means sum of above.
+ *
+ *  The key +:FREE+ is the number of object slots which are empty.
+ *
+ *  The key +:TOTAL+ is the total number of slots (which is the sum of
+ *  all of the other values).
  *
  *  If the optional argument +result_hash+ is given,
- *  it is overwritten and returned. This is intended to avoid probe effect.
+ *  it is overwritten and returned.
+ *  This is intended to avoid the probe effect.
  *
  *    h = {}
  *    ObjectSpace.count_objects(h)
diff --git a/pathname_builtin.rb b/pathname_builtin.rb
index 03b71f79868aac..60f936632fc120 100644
--- a/pathname_builtin.rb
+++ b/pathname_builtin.rb
@@ -1105,8 +1105,12 @@ def each_line(...) # :yield: line
   #
   def read(...) File.read(@path, ...) end
 
-  # See <tt>File.binread</tt>.  Returns all the bytes from the file, or the first +N+
-  # if specified.
+  # call-seq:
+  #   binread(length = nil, offset = 0) -> string or nil
+  #
+  # Behaves like #read, except that the file is opened in binary mode
+  # with ASCII-8BIT encoding.
+  #
   def binread(...) File.binread(@path, ...) end
 
   # See <tt>File.readlines</tt>.  Returns all the lines from the file.
@@ -1152,9 +1156,11 @@ def sysopen(...) File.sysopen(@path, ...) end
   #
   def write(...) File.write(@path, ...) end
 
-  # Writes +contents+ to the file, opening it in binary mode.
+  # call-seq:
+  #   binwrite(string, offset = 0, **opts) -> nonnegative_integer
   #
-  # See File.binwrite.
+  # Behaves like #write, except that the file is opened in binary mode
+  # with ASCII-8BIT encoding.
   def binwrite(...) File.binwrite(@path, ...) end
 
   # call-seq:
@@ -1342,10 +1348,34 @@ def realdirpath(...) self.class.new(File.realdirpath(@path, ...)) end
 
 class Pathname    # * FileTest *
 
-  # See <tt>FileTest.blockdev?</tt>.
+  # call-seq:
+  #   blockdev? => true or false
+  #
+  # Returns whether +self+ represents a block device
+  # (i.e., a random-access device):
+  #
+  #   Pathname.new('/dev/nvme0n1').blockdev? # => true
+  #   Pathname.new('/dev/loop0').blockdev?   # => true
+  #   Pathname.new('/dev/tty').blockdev?     # => false
+  #   Pathname.new('/dev/null').blockdev?    # => false
+  #   Pathname.new('nosuch').blockdev?       # => false
+  #
+  # The returned value is OS-dependent; on Windows, almost always +false+.
   def blockdev?() FileTest.blockdev?(@path) end
 
-  # See <tt>FileTest.chardev?</tt>.
+  # call-seq:
+  #   chardev? => true or false
+  #
+  # Returns whether +self+ represents a character device
+  # (i.e., a sequential-access device):
+  #
+  #   Pathname.new('/dev/tty').chardev?     # => true
+  #   Pathname.new('/dev/null').chardev?    # => true
+  #   Pathname.new('/dev/nvme0n1').chardev? # => false
+  #   Pathname.new('/dev/loop0').chardev?   # => false
+  #   Pathname.new('nosuch').chardev?       # => false
+  #
+  # The returned value is OS-dependent; on Windows, almost always +false+.
   def chardev?() FileTest.chardev?(@path) end
 
   # Tests the file is empty.
diff --git a/test/io/wait/test_io_wait.rb b/test/io/wait/test_io_wait.rb
index ffe3b1f760a626..c532638e0990f9 100644
--- a/test/io/wait/test_io_wait.rb
+++ b/test/io/wait/test_io_wait.rb
@@ -23,7 +23,7 @@ def test_wait
     omit 'unstable on MinGW' if /mingw/ =~ RUBY_PLATFORM
     assert_nil @r.wait(0)
     @w.syswrite "."
-    sleep 0.1
+    IO.select([@r])
     assert_equal @r, @r.wait(0)
   end
 
diff --git a/tool/sync_default_gems.rb b/tool/sync_default_gems.rb
index 7c55ce8628ff13..5727ee00c57d1b 100755
--- a/tool/sync_default_gems.rb
+++ b/tool/sync_default_gems.rb
@@ -108,12 +108,6 @@ def lib((upstream, branch), gemspec_in_subdir: false)
     ]),
     "open-uri": lib("ruby/open-uri"),
     English: lib("ruby/English"),
-    cgi: repo("ruby/cgi", [
-      ["ext/cgi", "ext/cgi"],
-      ["lib/cgi/escape.rb", "lib/cgi/escape.rb"],
-      ["test/cgi/test_cgi_escape.rb", "test/cgi/test_cgi_escape.rb"],
-      ["test/cgi/update_env.rb", "test/cgi/update_env.rb"],
-    ]),
     date: repo("ruby/date", [
       ["doc/date", "doc/date"],
       ["ext/date", "ext/date"],
@@ -202,12 +196,6 @@ def lib((upstream, branch), gemspec_in_subdir: false)
     optparse: lib("ruby/optparse", gemspec_in_subdir: true).tap {
       it.mappings << ["doc/optparse", "doc/optparse"]
     },
-    pathname: repo("ruby/pathname", [
-      ["ext/pathname/pathname.c", "pathname.c"],
-      ["lib/pathname_builtin.rb", "pathname_builtin.rb"],
-      ["lib/pathname.rb", "lib/pathname.rb"],
-      ["test/pathname", "test/pathname"],
-    ]),
     pp: lib("ruby/pp"),
     prettyprint: lib("ruby/prettyprint"),
     prism: repo(["ruby/prism", "main"], [
@@ -445,7 +433,7 @@ def sync_default_gems(gem)
   end
 
   def check_prerelease_version(gem)
-    return if ["rubygems", "mmtk", "cgi", "pathname", "Onigmo"].include?(gem)
+    return if ["rubygems", "mmtk", "Onigmo"].include?(gem)
 
     require "net/https"
     require "json"